dev(extensions): [+] puterfs (copies memoryfs)

This extension has a copy of memoryfs which is exposed as `testfs`. The
purpose of this is to register a new filesystem type from an extension
to ensure it works as expected and to get feedback on a working example.

extensions/puterfs/package.json

@@ -0,0 +1,6 @@
+{
+    "main": "main.js",
+    "dependencies": {
+        "uuid": "^13.0.0"
+    }
+}